Frequency hopping spectral capacity enhancement of cellular networks

In the highly competitive mobile radio market the resource system spectrum is often shared between at least two system operators while the capacity demands and quality requirements are dramatically increasing. Wideband random frequency hopping (FH) in digital F/TDMA systems like GSM and its derivatives is a method of expanding the bandwidth used by a traffic channel, thereby creating frequency and interference diversity effects. In this paper the diversity effects of random FH are analysed by means of combined link and system level simulations of the GSM full rate speech channel embedded in different network simulation environments in different network configurations. The results indicate that even without power control the use of random FH with discontinuous transmission (DTX) provides both spectral capacity enhancement and improved quality for slow-moving mobiles in particular. We show that with a total of 24 frequencies available for traffic a fractionally loaded 1/3 reuse scheme yields a spectral capacity increase of 84% compared with a non-hopping 4/12 reuse scheme at the same speech quality level